1. Field of the Invention
The present invention relates to an X-ray generating apparatus used in non-destructive X-ray imaging and diagnosis and an X-ray imaging system having the same.
2. Description of the Related Art
An X-ray generating apparatus is widely used in medical diagnosis and non-destructive testing to generate images of various structures, which images may be used to detect defects in the structures.
Generally, a medical X-ray generating apparatus has a structure in which thermal electrons are emitted from a cathode filament which is heated to high temperature, and then the emitted electrons are accelerated so as to collide with a rotating anode target to, to thereby generate X-rays.
In such a structure in which thermal electrons collide with the rotating anode target, a large amount of X-rays are generated. However, with such apparatus, several peripheral devices are needed, such as, to heat the cathode filament, a rotating device to rotate the anode, and a cooling device may be needed, with the combined result that the volume and weight of the X-ray generating apparatus is substantially increased. Most of the thermal electrons emitted from the cathode filament are converted into heat, and remaining the thermal electrons are used to generate X-rays. For this reason, X-ray generating apparatus are generally inefficient and exhibit low resolution.
In recent years, research has been conducted into a field emission display (FED) type X-ray generating apparatus (hereinafter, referred to as a flat plate type X-ray generating apparatus). The flat X-ray generating apparatus has a structure in which needle-shaped emitters each having a size of about several tens of a nanometer (nm) are disposed on a flat plate, and a high electric field is applied to the emitters so that electrons emitted from the emitters are forced to collide with an anode target so as to generate X-rays.
In the flat plate type X-ray generating apparatus, the size of the apparatus is small, and X-ray generation is efficiently controlled. However, it is difficult to generate an amount of X-rays that are sufficiently collimated for X-ray imaging. In particular, it is difficult to collimate X-rays in a direction in parallel to each other (that is, in a plurality of parallel paths). For this reason, the flat plate type X-ray generating apparatus is not widely used for medical purposes.